Remember the proverbial expression 'not seeing the wood for the trees'? You need to see the 'wood' first, then delve in and start examining the individual 'trees', meaning the individual items which you will be breaking down later. So a great point is to make sure that you have that overarching vision _ and if you cannot find one, then maybe it is an indication that you are obsessing on a few technical aspects that do not necessarily make up a whole business as you had imagined it. A business that makes sense and is going to be sustainable in the future is one that has that clear vision within which all the smaller parts contribute to make it successful.
Production Operation _ If a product must be manufactured, what is the process? Will the work be done on_site or subcontracted? Who are the subcontractor(s)? If on_site, what space, equipment, machinery, production employees are needed? What suppliers are needed? Who are they? How will quality be assured? What is the anticipated production output? What established credit lines do you have? Possible Data Sources: local Chamber of Commerce; yellow pages; trade associations.